Celestial navigation procedures generally require cumbersome equipment and volumes of source materials in addition to considerable navigational training for their use. For example, plotting boards, charts, and volumes of tables are all commonly needed along with the sextant, transit, or other instruments employed for celestial observation. While the space requirements may not be objectionable on board ship, they may become so where space is at a premium, as on a smaller vessel, in aircraft, or during land exploration. Efforts to develop equipment which requires less space, and which may be easier to use for a person without extensive navigational training, have met with only limited success, presumably because voluminous tables may still be required, or because the instruments have been too complex, delicate, or difficult to operate, or because such instruments have for all practical purposes been limited to the sighting of select reference stars, such as the North Star.
References illustrative of the art are U.S. Pat. Nos. 2,566,312 (Cable), 2,316,466 (Storer), E. S. Maloney, Dutton's Navigation (Navel Institute Press, Anapolis, Md., 1978), and Bowditch, The American Practical Navigator.